The invention relates to marking of industrial products or individual parts thereof utilizing a high energy beam to create a predetermine pattern of alphanumeric or other company markings as is usual in part in industrial practice.
The formation or burning-in of symbols can be performed not only by a laser beam but also by a spark-erosive method or by means of a high-pressure water jet. In the case of a water jet, although one would not really say "burning-in", a high-pressure water jet also leaves behind a track on softer materials. A burning-in with laser beam in particular or by means of spark erosion comes into consideration in particular for hard surfaces. However, with a laser beam any type of material can be marked.
In the marking of industrial products, it is often desirable to apply not only an alphanumeric marking but also an informationally similar, readily machine-readable additional coding (cf. for example German Patent Specification 2,616,436). A disadvantage of the dual marking is the relatively large space requirement for the two different types of marking and, in the case of a marking incorporated in the material, the relatively high production effort for the two markings applied next to each other.
An object of the invention is to provide a dual type of informationally similar marking of industrial products which can be produced in a space-saving and cost-effective way.
This object is achieved according to the invention by providing a second pattern of deeper "burnt-in" predetermined patterns in the first "burnt-in" pattern. The additional coding is accommodated in a space-saving way by virtue of a character-integrated application and can, moreover, be produced in the same operation as the marking of the first type by virtue of a greater burnt-in depth. Thanks to the use of high-resolving sensors, the greater burnt-in depth and the distribution of the deeper burnt-in locations can be readily detected and consequently each individual symbol is machine-readable even at the additional coding.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.